In general, a puncture device has a lancet which is moved together with a lancet holder by the elastic force of a spring to pierce a skin. As an example of such puncture device, a device which allows a user to adjust a piercing depth of a lancet relative to a skin has been proposed (see, for example, Patent Literature 1). According to such puncture device, there is a possibility that a skin is pierced plural times caused by expanding and contracting motion of the spring unless energy imparted to the lancet holder is appropriately absorbed. Moreover, even if the kinetic energy of the lancet holder can be appropriately absorbed, there is a case in which a user feels a pain when the skin is pierced because of an impact caused when the kinetic energy is absorbed. Accordingly, there has been proposed a puncture device with a cam mechanism in order to avoid plural times piercing and to reduce the pain when the skin is pierced (see, for example, Patent Literature 2).
Meanwhile, a general lancet is attached in a lancet holder, and used after a protecting cover is removed. According to such lancet, a puncture needle is exposed when the lancet is attached or discarded, so that there is a possibility that a fingertip or the like is hurt by the puncture needle. Therefore, there has been proposed a lancet, so called a safety lancet, configured to be retained in a casing so as to be bound in the casing when a user discards the lancet (see, for example, Patent Literature 3). According to such lancet, a puncture needle is surrounded by the casing when the lancet is attached, and the lancet is bound in the casing when discarded, resulting in reduction of the possibility that the puncture needle hurts the fingertip or the like when the lancet is attached or discarded.
Consequently, in order to reduce a pain when a skin is pierced and to accomplish a safeness, it is preferable to use the puncture device employing a cam mechanism, and in order to pierce the skin more safely, it is preferable to use the device in combination with the safety lancet. However, when the puncture device employs both cam mechanism and safety lancet combined together, it is difficult to further provide a mechanism of adjusting a piercing depth. For example, according to the puncture device employing a cam mechanism, as the operation of a component each configuring the cam mechanism is linked with each other, the moving distance of the lancet holder is regulated by the shape of a component or the like. Conversely, according to the safety lancet, it is necessary to regulate a positional relation between the casing and the lancet so that the lancet is appropriately bound in the casing when attached and discarded.
Patent Literature 1: Unexamined Japanese Patent Application KOKAI Publication No. 2004-344291
Patent Literature 2: Unexamined Japanese Patent Application KOKAI Publication No. 2004-344292
Patent Literature 3: Unexamined Japanese Patent Application KOKAI Publication No. 2005-312763